Ideas:
Wall that you can jump over (hurdle)
Wall that you can vault over
Wall that you need to climb over
Wall that you need a rope to climb over
Balance beam
Tunnel to climb through
"Barbed wire" low crawl
Long jump over "water hazard"
High climbing rope

Ugly Dougly wrote:Ideas:Wall that you can jump over (hurdle)Wall that you can vault overWall that you need to climb overWall that you need a rope to climb overBalance beamTunnel to climb through"Barbed wire" low crawlLong jump over "water hazard"High climbing rope

Wall that is sentient and will chase you and grab you
Tunnel that gradually diminishes in size and, in so doing, shrinks you
Gigantic boulder that rolls downhill and could crush you
Gigantic boulder that can somehow also roll uphill and crush you
Flying alligator arena
Bookmaker's lounge for flying alligator arena
Imbalance beam (attempting to cross it interferes with your seratonin)

I think an obstacle course would be really cool, although I'm a newbie around here so I'm probably not considering all the relevant complications. I will say that you can make some decent hurdles and crawl-under areas out of simple PVC, and if you don't actually glue it together then it generally doesn't break when people fall on it. Stakes and P-cord are great for crawling under, of course, even if less viscerally exciting than razor wire.